Two hours later, Yang Yu returned carrying an impressive load of Source Crystals—the smallest no bigger than a peanut, the largest nearly half the size of a football. Their quality ranged from the most ordinary First‑Tier Midnight Black to the rare Fifth‑Tier Azure Chaoshi.
A quick estimation made Ye Cheng almost faint with delight. Their haul was enough to make professional mining teams pound their chests in envy. Even after paying the rental for the dust‑proof vehicle and deducting theoretical taxes, they would still clear a profit of well over a hundred thousand credits. She carefully stored every stone away and checked the time. "Should we start heading back now?"
Yang Yu didn't answer immediately. He opened the display projected from his Subspace Ring, frowned, and said, "We might have to stay here a while longer."
Puzzled, Ye Cheng leaned closer as he expanded the holographic feed. The footage came from the car's external cameras. The once‑quiet wasteland had transformed into a roaring sandstorm—gale winds drove waves of dust and grit across the landscape, and even their heavy vehicle swayed under the assault. The sky was a bruise‑colored blur; it could hardly be called daylight anymore. Ye Cheng had no doubt that if she stepped out now, she'd be blown half a mile before she reached the car.
Her face fell. "How long will the storm last?" she asked, clinging to a shred of hope.
"Optimistically, three days," Yang Yu replied after a moment's thought. "But it could just as easily go on for a week."
Ye Cheng slumped down, shoulders drooping. Being prepared was one thing; realizing she might have to live underground for days was another. The air down here was damp, still, and lifeless—just the two of them in endless quiet. They had enough food and water for a month, but even a day in this tomb‑like silence felt like slow torture.
Yang Yu, practical as always, began setting up sleeping bags and small living supplies.
Ye Cheng joined in helplessly, mind wandering. He's a good kid, sure. Just… he barely talks at all. Spending a week like this, she thought, she might forget how human conversation even worked.
Once their temporary camp was arranged, Yang Yu started cooking. Ye Cheng, bored beyond endurance, propped her chin on her hand. "Tubby," she said suddenly—her teasing nickname for him—"sing me a song."
The ever‑capable Yang Yu froze for once, a flicker of embarrassment on his face. "I'm sorry, Master. I… don't know how to sing."
She had expected that. With a sigh, she buried her head in her arms. "So boring… Do we really have to stay here for three whole days?"
Yang Yu wisely kept silent; he didn't dare mention the possibility of an entire week. He didn't want to risk her next whim being dance for me, slave.
Before long, the food was ready. He brought her a steaming bowl and quietly returned to prepare his own portion. Ye Cheng scooted beside him—if she didn't force some conversation, she was sure her social instincts would rust out. "By the way, what kind of food do you like, Tubby?"
Yang Yu thought for a second. "Anything edible."
"…And what do you like to drink?"
"Anything drinkable."
Ye Cheng gnashed her teeth. "Then what's your ideal in life, huh?" She added inwardly, If he dares say something like 'a small farm and clean spring water,' I swear—
To her surprise, Yang Yu paused, turned, and looked her straight in the eyes. His voice was firm, steady.
"To make sure that no mixed‑blood will ever be bullied again."
The words hung in the air between them. Both froze, startled. Yang Yu's heart sank an instant later. He had grown too comfortable—how could he have said such a thing to his master? Words like that were technically treason.
He turned back to his cooking, spine taut. "Forgive me, Master," he murmured. "I meant no offense—"
Before he could finish, he felt a weight rest gently against his back.
In the tiny pocket of silence, the only sound was the hum of the portable stove. Ye Cheng leaned her forehead lightly against him, and neither spoke.
Then, a sharp beeping broke the stillness—from both their Subspace Rings.
Ye Cheng blinked, confused; she wasn't familiar with all of the ring's functions. The noise was insistent, urgent. Yang Yu reacted instantly, tapping a sequence of commands. His expression hardened. "Master… we might not be able to return."
The holographic window glowed a dull gray‑blue. "Our vehicle is under attack."
"What?" she blurted, lost.
He had no time to explain. Abandoning even the meal on the stove, he grabbed her roughly by the arm. "Forgive me, Master."
A brief sting at her neck—and darkness swallowed her.
When Ye Cheng collapsed unconscious, Yang Yu caught her, then straightened, voice low and steady. "Lei Ze."
A black humanoid mech shimmered into existence in the open cavern. The armor bore scars and dents but gleamed with careful maintenance. Cradling Ye Cheng in his arms, Yang Yu strode to the lifting ramp, ascended, and sealed them both within the cockpit.
He barely fastened the restraints before his hands flew over the controls.
Luck—or misfortune—had found them. They had run afoul of professional crystal raiders: illegal miners who ignored registration laws and hunted for mid‑ to high‑grade Source Crystals. These operations usually moved in small squads of ten or more, armed, ruthless, and often equipped well enough to fight patrol mechs head‑on. Those unlucky enough to meet them rarely left witnesses.
Smuggling refined Source Crystals was lucrative. The government monopolized legal sales, releasing only a trickle to the market at exorbitant, tax‑bloated prices. Most went straight to industrial or military mechs, so collectors and enthusiasts eagerly sought contraband sources instead.
Because Ye Cheng had come along, they hadn't gone too far into the mine system. For raiders to work during a dust storm meant they were using mechs. If Yang Yu didn't move now, they would be found and buried alive.
The tunnels were narrow and treacherous—no place for open combat. Worse, Lei Ze had yet to receive proper repairs since its last battle, its power core still partially crippled. A frontal confrontation would be suicide. Yang Yu decided to retreat, steering the mech toward the first tunnel they'd entered earlier.
The mine branched in every direction; in some spots, a few strikes could break through to a neighboring shaft. Lei Ze's physical ammunition was spent, and only the crystal they had just fed into its Element Core powered it now—barely twenty percent charge. If rationed carefully, it might hold until they reached the surface.
Lei Ze was the first elemental mech ever built by Yang Jin, later given to Yang Yu himself. Despite flaws, it remained a masterpiece—classified at Crimson Zenith, equivalent to elite military‑grade machines.
Years ago, when his master's convoy was ambushed, Yang Yu had piloted Lei Ze alone against dozens of enemy Crimson‑class mechs and even a Twilight‑class flagship mech. Lei Ze had held its ground—until its power core burned out and Yang Yu fell grievously wounded.
The current machine lacked advanced AI; every maneuver required precision from the pilot. Navigating the tight shafts while blasting narrow passages was grueling.
Before long, the cockpit grew unbearably hot without its auto‑cooling system. Sweat ran down Yang Yu's temples, but he didn't slow. The raiders outside had almost certainly found their car—and he knew the kind of men they were. They would not stop until the mine was a tomb.
If he had brought Ye Cheng underground, then he would bring her back alive—no matter what.
Heat blurred his vision. Beside him, Ye Cheng stirred restlessly, beads of sweat glistening on her flushed face.
His blow hadn't been harsh; he knew she would soon wake.
He hesitated. Knocking her out again would keep her unaware—but something inside him resisted. He glanced sideways. Her lashes trembled, cheeks flushed crimson in the heat, and he remembered the gentle weight of her head on his back.
For once, he chose to gamble.
He kept piloting, weaving Lei Ze through twisting caverns.
Minutes later, Ye Cheng groaned awake. The cockpit's narrow walls and countless control panels told her instantly what had happened. Rubbing her numb neck, she sat up. "How bad is it?"
Yang Yu answered without turning. "It'll take at least another half hour to break through to the surface—if the mech holds and we're not caught first."
She blinked. "Who's chasing us?"
"The crystal raiders. Outlaws. If they catch us, they'll kill us." He paused. "Master, I'm sorry."
Ye Cheng cuffed him lightly on the back of the head. "Forget it. I'm up now, aren't I?" She stared at the forest of buttons and switches before her—mind spinning.
Realizing she was useless at mech controls, she fell silent for a while, thinking hard. Then she asked, sweating, "If those raiders came here, doesn't that mean there's something valuable in this mine?" Of course, she had already secretly taken one Azure Chaoshi crystal herself.
Yang Yu remembered the similar crystal he had fed into Lei Ze's energy core and nodded. "Probably. They must be using professional scanners."
"Then why are we running? Why not dig more?"
He almost choked. Was she serious? With the core burning at this rate, they'd be cooked inside before reaching daylight—and she wanted to keep mining?
He swallowed the retort and forced a polite tone. "This mech's condition may not allow—"
Before he could finish, Ye Cheng reached out and cupped his face, turning him toward her. Her gaze was steady, voice clear.
"No matter what you see next," she said, "don't ask me any questions—and don't ever tell anyone."
He thought back to the strange traces of mech activity he'd seen when he first found her in the forest and understood enough to stay silent. He raised his right hand solemnly. "I swear I won't ask, and I won't speak of it."
Ye Cheng drew a breath, eyes resolute, and pressed her Subspace Ring.
"Shennong."